use Buffer.from instead of new Buffer (#181)

fixes #180

Author: sibelius

src/utils/base64.js

@@ -11,9 +11,9 @@
 export type Base64String = string;
 
 export function base64(i: string): Base64String {
-  return new Buffer(i, 'utf8').toString('base64');
+  return Buffer.from(i, 'utf8').toString('base64');
 }
 
 export function unbase64(i: Base64String): string {
-  return new Buffer(i, 'base64').toString('utf8');
+  return Buffer.from(i, 'base64').toString('utf8');
 }